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DSolve::overdet NDSolve::overdet NDSolveValue::overdet ParametricNDSolve::overdet ParametricNDSolveValue::overdet RSolve::overdet

DSolve::overdet NDSolve::overdet NDSolveValue::overdet ParametricNDSolve::overdet ParametricNDSolveValue::overdet RSolve::overdet

Details

  • This message is generated when the first argument of the indicated function includes inconsistent equations.
  • Off[message] switches off the message; On[message] switches it on. For example: Off[DSolve::overdet].

Examples

Basic Examples  (3)

An error occurs because of conflicting equations for f'[x]:

Wolfram Language code: DSolve[{f'[x] == f[x], f'[x] == 2}, f[x], x]

An error occurs because of a faulty equation setup:

Wolfram Language code: eqns = { D[u[x, y], x, x] == -D[u[x, y], y, y] == NeumannValue[Exp[-10], x == 1], u[-1, y] == Exp[-10], u[x, 1] == Exp[-10 x ^ 2], u[x, -1] == Exp[-10 x ^ 2]}; NDSolve[eqns, u, {x, -1, 1}, {y, -1, 1}];

Note the two Equal instances in the equation. Adjusting the equation fixes the problem:

Wolfram Language code: eqns = { D[u[x, y], x, x] + D[u[x, y], y, y] == NeumannValue[Exp[-10], x == 1], u[-1, y] == Exp[-10], u[x, 1] == Exp[-10 x ^ 2], u[x, -1] == Exp[-10 x ^ 2]}; NDSolve[eqns, u, {x, -1, 1}, {y, -1, 1}]

An error occurs because of a faulty initial condition setup:

Wolfram Language code: ics = Θ[t, x] == 0; NDSolveValue[{Inactive[Div][{{-0.02}} . Inactive[Grad][Θ[t, x], {x}], {x}] + 1000 Θ^(1, 0)[t, x] == NeumannValue[t, x == 0], ics}, Θ, {t, 0, 600}, x∈Line[{{0}, {1 / 5}}]]

Note that the initial condition needs to be specified at a numerical value of the initial time. Fixing the initial condition specification solves the problem:

Wolfram Language code: ics = Θ[0, x] == 0; NDSolveValue[{Inactive[Div][{{-0.02}} . Inactive[Grad][Θ[t, x], {x}], {x}] + 1000 Θ^(1, 0)[t, x] == NeumannValue[t, x == 0], ics}, Θ, {t, 0, 600}, x∈Line[{{0}, {1 / 5}}]]